linux/drivers/serial/altera_uart.c
Anton Vorontsov 70eebd0b60 altera_uart: Don't use plain integer as NULL pointer
Fixes sparse warning.

Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
2010-10-22 10:20:09 -07:00

609 lines
16 KiB
C

/*
* altera_uart.c -- Altera UART driver
*
* Based on mcf.c -- Freescale ColdFire UART driver
*
* (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
* (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
* (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/altera_uart.h>
#define DRV_NAME "altera_uart"
#define SERIAL_ALTERA_MAJOR 204
#define SERIAL_ALTERA_MINOR 213
/*
* Altera UART register definitions according to the Nios UART datasheet:
* http://www.altera.com/literature/ds/ds_nios_uart.pdf
*/
#define ALTERA_UART_SIZE 32
#define ALTERA_UART_RXDATA_REG 0
#define ALTERA_UART_TXDATA_REG 4
#define ALTERA_UART_STATUS_REG 8
#define ALTERA_UART_CONTROL_REG 12
#define ALTERA_UART_DIVISOR_REG 16
#define ALTERA_UART_EOP_REG 20
#define ALTERA_UART_STATUS_PE_MSK 0x0001 /* parity error */
#define ALTERA_UART_STATUS_FE_MSK 0x0002 /* framing error */
#define ALTERA_UART_STATUS_BRK_MSK 0x0004 /* break */
#define ALTERA_UART_STATUS_ROE_MSK 0x0008 /* RX overrun error */
#define ALTERA_UART_STATUS_TOE_MSK 0x0010 /* TX overrun error */
#define ALTERA_UART_STATUS_TMT_MSK 0x0020 /* TX shift register state */
#define ALTERA_UART_STATUS_TRDY_MSK 0x0040 /* TX ready */
#define ALTERA_UART_STATUS_RRDY_MSK 0x0080 /* RX ready */
#define ALTERA_UART_STATUS_E_MSK 0x0100 /* exception condition */
#define ALTERA_UART_STATUS_DCTS_MSK 0x0400 /* CTS logic-level change */
#define ALTERA_UART_STATUS_CTS_MSK 0x0800 /* CTS logic state */
#define ALTERA_UART_STATUS_EOP_MSK 0x1000 /* EOP written/read */
/* Enable interrupt on... */
#define ALTERA_UART_CONTROL_PE_MSK 0x0001 /* ...parity error */
#define ALTERA_UART_CONTROL_FE_MSK 0x0002 /* ...framing error */
#define ALTERA_UART_CONTROL_BRK_MSK 0x0004 /* ...break */
#define ALTERA_UART_CONTROL_ROE_MSK 0x0008 /* ...RX overrun */
#define ALTERA_UART_CONTROL_TOE_MSK 0x0010 /* ...TX overrun */
#define ALTERA_UART_CONTROL_TMT_MSK 0x0020 /* ...TX shift register empty */
#define ALTERA_UART_CONTROL_TRDY_MSK 0x0040 /* ...TX ready */
#define ALTERA_UART_CONTROL_RRDY_MSK 0x0080 /* ...RX ready */
#define ALTERA_UART_CONTROL_E_MSK 0x0100 /* ...exception*/
#define ALTERA_UART_CONTROL_TRBK_MSK 0x0200 /* TX break */
#define ALTERA_UART_CONTROL_DCTS_MSK 0x0400 /* Interrupt on CTS change */
#define ALTERA_UART_CONTROL_RTS_MSK 0x0800 /* RTS signal */
#define ALTERA_UART_CONTROL_EOP_MSK 0x1000 /* Interrupt on EOP */
/*
* Local per-uart structure.
*/
struct altera_uart {
struct uart_port port;
struct timer_list tmr;
unsigned int sigs; /* Local copy of line sigs */
unsigned short imr; /* Local IMR mirror */
};
static u32 altera_uart_readl(struct uart_port *port, int reg)
{
struct altera_uart_platform_uart *platp = port->private_data;
return readl(port->membase + (reg << platp->bus_shift));
}
static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
{
struct altera_uart_platform_uart *platp = port->private_data;
writel(dat, port->membase + (reg << platp->bus_shift));
}
static unsigned int altera_uart_tx_empty(struct uart_port *port)
{
return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
}
static unsigned int altera_uart_get_mctrl(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned int sigs;
sigs = (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0;
sigs |= (pp->sigs & TIOCM_RTS);
return sigs;
}
static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
pp->sigs = sigs;
if (sigs & TIOCM_RTS)
pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
else
pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
}
static void altera_uart_start_tx(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
}
static void altera_uart_stop_tx(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
}
static void altera_uart_stop_rx(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
}
static void altera_uart_break_ctl(struct uart_port *port, int break_state)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
if (break_state == -1)
pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
else
pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
spin_unlock_irqrestore(&port->lock, flags);
}
static void altera_uart_enable_ms(struct uart_port *port)
{
}
static void altera_uart_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old)
{
unsigned long flags;
unsigned int baud, baudclk;
baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
baudclk = port->uartclk / baud;
if (old)
tty_termios_copy_hw(termios, old);
tty_termios_encode_baud_rate(termios, baud, baud);
spin_lock_irqsave(&port->lock, flags);
uart_update_timeout(port, termios->c_cflag, baud);
altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
spin_unlock_irqrestore(&port->lock, flags);
}
static void altera_uart_rx_chars(struct altera_uart *pp)
{
struct uart_port *port = &pp->port;
unsigned char ch, flag;
unsigned short status;
while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) &
ALTERA_UART_STATUS_RRDY_MSK) {
ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
flag = TTY_NORMAL;
port->icount.rx++;
if (status & ALTERA_UART_STATUS_E_MSK) {
altera_uart_writel(port, status,
ALTERA_UART_STATUS_REG);
if (status & ALTERA_UART_STATUS_BRK_MSK) {
port->icount.brk++;
if (uart_handle_break(port))
continue;
} else if (status & ALTERA_UART_STATUS_PE_MSK) {
port->icount.parity++;
} else if (status & ALTERA_UART_STATUS_ROE_MSK) {
port->icount.overrun++;
} else if (status & ALTERA_UART_STATUS_FE_MSK) {
port->icount.frame++;
}
status &= port->read_status_mask;
if (status & ALTERA_UART_STATUS_BRK_MSK)
flag = TTY_BREAK;
else if (status & ALTERA_UART_STATUS_PE_MSK)
flag = TTY_PARITY;
else if (status & ALTERA_UART_STATUS_FE_MSK)
flag = TTY_FRAME;
}
if (uart_handle_sysrq_char(port, ch))
continue;
uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
flag);
}
tty_flip_buffer_push(port->state->port.tty);
}
static void altera_uart_tx_chars(struct altera_uart *pp)
{
struct uart_port *port = &pp->port;
struct circ_buf *xmit = &port->state->xmit;
if (port->x_char) {
/* Send special char - probably flow control */
altera_uart_writel(port, port->x_char, ALTERA_UART_TXDATA_REG);
port->x_char = 0;
port->icount.tx++;
return;
}
while (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_TRDY_MSK) {
if (xmit->head == xmit->tail)
break;
altera_uart_writel(port, xmit->buf[xmit->tail],
ALTERA_UART_TXDATA_REG);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (xmit->head == xmit->tail) {
pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
}
}
static irqreturn_t altera_uart_interrupt(int irq, void *data)
{
struct uart_port *port = data;
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned int isr;
isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
spin_lock(&port->lock);
if (isr & ALTERA_UART_STATUS_RRDY_MSK)
altera_uart_rx_chars(pp);
if (isr & ALTERA_UART_STATUS_TRDY_MSK)
altera_uart_tx_chars(pp);
spin_unlock(&port->lock);
return IRQ_RETVAL(isr);
}
static void altera_uart_timer(unsigned long data)
{
struct uart_port *port = (void *)data;
struct altera_uart *pp = container_of(port, struct altera_uart, port);
altera_uart_interrupt(0, port);
mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
}
static void altera_uart_config_port(struct uart_port *port, int flags)
{
port->type = PORT_ALTERA_UART;
/* Clear mask, so no surprise interrupts. */
altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG);
/* Clear status register */
altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG);
}
static int altera_uart_startup(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned long flags;
int ret;
if (!port->irq) {
setup_timer(&pp->tmr, altera_uart_timer, (unsigned long)port);
mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
return 0;
}
ret = request_irq(port->irq, altera_uart_interrupt, IRQF_DISABLED,
DRV_NAME, port);
if (ret) {
pr_err(DRV_NAME ": unable to attach Altera UART %d "
"interrupt vector=%d\n", port->line, port->irq);
return ret;
}
spin_lock_irqsave(&port->lock, flags);
/* Enable RX interrupts now */
pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
static void altera_uart_shutdown(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
/* Disable all interrupts now */
pp->imr = 0;
writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
spin_unlock_irqrestore(&port->lock, flags);
if (port->irq)
free_irq(port->irq, port);
else
del_timer_sync(&pp->tmr);
}
static const char *altera_uart_type(struct uart_port *port)
{
return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
}
static int altera_uart_request_port(struct uart_port *port)
{
/* UARTs always present */
return 0;
}
static void altera_uart_release_port(struct uart_port *port)
{
/* Nothing to release... */
}
static int altera_uart_verify_port(struct uart_port *port,
struct serial_struct *ser)
{
if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
return -EINVAL;
return 0;
}
/*
* Define the basic serial functions we support.
*/
static struct uart_ops altera_uart_ops = {
.tx_empty = altera_uart_tx_empty,
.get_mctrl = altera_uart_get_mctrl,
.set_mctrl = altera_uart_set_mctrl,
.start_tx = altera_uart_start_tx,
.stop_tx = altera_uart_stop_tx,
.stop_rx = altera_uart_stop_rx,
.enable_ms = altera_uart_enable_ms,
.break_ctl = altera_uart_break_ctl,
.startup = altera_uart_startup,
.shutdown = altera_uart_shutdown,
.set_termios = altera_uart_set_termios,
.type = altera_uart_type,
.request_port = altera_uart_request_port,
.release_port = altera_uart_release_port,
.config_port = altera_uart_config_port,
.verify_port = altera_uart_verify_port,
};
static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
#if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
int __init early_altera_uart_setup(struct altera_uart_platform_uart *platp)
{
struct uart_port *port;
int i;
for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS && platp[i].mapbase; i++) {
port = &altera_uart_ports[i].port;
port->line = i;
port->type = PORT_ALTERA_UART;
port->mapbase = platp[i].mapbase;
port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
port->iotype = SERIAL_IO_MEM;
port->irq = platp[i].irq;
port->uartclk = platp[i].uartclk;
port->flags = UPF_BOOT_AUTOCONF;
port->ops = &altera_uart_ops;
port->private_data = platp;
}
return 0;
}
static void altera_uart_console_putc(struct uart_port *port, const char c)
{
while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_TRDY_MSK))
cpu_relax();
writel(c, port->membase + ALTERA_UART_TXDATA_REG);
}
static void altera_uart_console_write(struct console *co, const char *s,
unsigned int count)
{
struct uart_port *port = &(altera_uart_ports + co->index)->port;
for (; count; count--, s++) {
altera_uart_console_putc(port, *s);
if (*s == '\n')
altera_uart_console_putc(port, '\r');
}
}
static int __init altera_uart_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
return -EINVAL;
port = &altera_uart_ports[co->index].port;
if (!port->membase)
return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver altera_uart_driver;
static struct console altera_uart_console = {
.name = "ttyAL",
.write = altera_uart_console_write,
.device = uart_console_device,
.setup = altera_uart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &altera_uart_driver,
};
static int __init altera_uart_console_init(void)
{
register_console(&altera_uart_console);
return 0;
}
console_initcall(altera_uart_console_init);
#define ALTERA_UART_CONSOLE (&altera_uart_console)
#else
#define ALTERA_UART_CONSOLE NULL
#endif /* CONFIG_ALTERA_UART_CONSOLE */
/*
* Define the altera_uart UART driver structure.
*/
static struct uart_driver altera_uart_driver = {
.owner = THIS_MODULE,
.driver_name = DRV_NAME,
.dev_name = "ttyAL",
.major = SERIAL_ALTERA_MAJOR,
.minor = SERIAL_ALTERA_MINOR,
.nr = CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
.cons = ALTERA_UART_CONSOLE,
};
static int __devinit altera_uart_probe(struct platform_device *pdev)
{
struct altera_uart_platform_uart *platp = pdev->dev.platform_data;
struct uart_port *port;
struct resource *res_mem;
struct resource *res_irq;
int i = pdev->id;
/* -1 emphasizes that the platform must have one port, no .N suffix */
if (i == -1)
i = 0;
if (i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
return -EINVAL;
port = &altera_uart_ports[i].port;
res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res_mem)
port->mapbase = res_mem->start;
else if (platp->mapbase)
port->mapbase = platp->mapbase;
else
return -EINVAL;
res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (res_irq)
port->irq = res_irq->start;
else if (platp->irq)
port->irq = platp->irq;
port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
if (!port->membase)
return -ENOMEM;
port->line = i;
port->type = PORT_ALTERA_UART;
port->iotype = SERIAL_IO_MEM;
port->uartclk = platp->uartclk;
port->ops = &altera_uart_ops;
port->flags = UPF_BOOT_AUTOCONF;
port->private_data = platp;
uart_add_one_port(&altera_uart_driver, port);
return 0;
}
static int __devexit altera_uart_remove(struct platform_device *pdev)
{
struct uart_port *port = &altera_uart_ports[pdev->id].port;
uart_remove_one_port(&altera_uart_driver, port);
return 0;
}
static struct platform_driver altera_uart_platform_driver = {
.probe = altera_uart_probe,
.remove = __devexit_p(altera_uart_remove),
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
.pm = NULL,
},
};
static int __init altera_uart_init(void)
{
int rc;
rc = uart_register_driver(&altera_uart_driver);
if (rc)
return rc;
rc = platform_driver_register(&altera_uart_platform_driver);
if (rc) {
uart_unregister_driver(&altera_uart_driver);
return rc;
}
return 0;
}
static void __exit altera_uart_exit(void)
{
platform_driver_unregister(&altera_uart_platform_driver);
uart_unregister_driver(&altera_uart_driver);
}
module_init(altera_uart_init);
module_exit(altera_uart_exit);
MODULE_DESCRIPTION("Altera UART driver");
MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);